Google is your friend.
Only you will know what is suitable for you, will you shoot 5x4 film, medium format or just 35mm! Whatever you buy, make sure it is complete and works in every way. It's unlikely you will get any spare parts for this stuff these days.
I suggest you try to buy something locally so that you can see it yourself first before committing to buy, as you would have to on Evilbay. Try the trading post or maybe your local photographic dealers, or maybe clubs, and have a look around first. Do some research on the interweb on models you might be considering.
There's no problem buying something on Evilbay as long as you are guaranteed the item is complete and works 100% and preferably have an option to get your money back if it isn't.
JJ